GENETIC ANIMAL MODELS CORE: PROJECT SUMMARY The Genetic Animal Models core will be co-directed by Hans-Christian Reinecker and Cornelis Terhorst. Services offered by the Genetic Animals Models Core include (1) breeding and maintenance of mutant mouse stocks, (2) characterization of murine models, (3) cell isolation from and characterization of murine models of IBD; (4) cell type-specific gene targeting and depletion; (5) bone marrow transfers and adoptive T cell transfers; (6) maintenance of GFP- and RFP-based reporter mice; (7) in vivo tracking of fluorescent cells and labeled bacteria; (8) mouse brightfield and fluorescent endoscopy, (9) whole-body imaging of bioluminescent and fluorescent signals, (10) intravital imaging of immune cells using multiphoton intravital microscopy, and (12) new murine model development. Within the 163 genetic associations currently known to be associated with risk of IBD, an increasing number of rare variants have highlighted the significance of the relationship between intracellular responses to microbes and regulation of adaptive immunity in the pathogenesis of IBD. However, the in vivo functional context in which these genetic variations affect epithelial intestinal function and immune responses remains to be elucidated. To address this need, the Core will assist investigators in using or developing model systems to examine the cell-specific function of variants, and will provide support for examining the functional role of these variants and their contribution to barrier function and innate and adaptive immunity. The specific aims of the Genetic Animal Models Core are to (1) support investigations in mice aimed at elucidating the contribution of IBD-related genetic variants and related genes to the pathogenesis of IBD in humans; (2) facilitate functional in vitro and in vivo imaging of cellular responses and migration in the mucosal and peripheral immune system; and (3) support sharing of model systems and tools to foster collaborations among CSIBD investigators.